// SPDX-License-Identifier: GPL-2.0-only
/*
 * Copyright (C) ST-Ericsson SA 2012
 *
 * Battery temperature driver for AB8500
 *
 * Author:
 *      Johan Palsson <johan.palsson@stericsson.com>
 *      Karl Komierowski <karl.komierowski@stericsson.com>
 *      Arun R Murthy <arun.murthy@stericsson.com>
 */

#include <linux/init.h>
#include <linux/module.h>
#include <linux/device.h>
#include <linux/interrupt.h>
#include <linux/delay.h>
#include <linux/slab.h>
#include <linux/platform_device.h>
#include <linux/power_supply.h>
#include <linux/completion.h>
#include <linux/workqueue.h>
#include <linux/jiffies.h>
#include <linux/of.h>
#include <linux/mfd/core.h>
#include <linux/mfd/abx500.h>
#include <linux/mfd/abx500/ab8500.h>
#include <linux/mfd/abx500/ab8500-bm.h>
#include <linux/iio/consumer.h>

#define VTVOUT_V                        1800

#define BTEMP_THERMAL_LOW_LIMIT         -10
#define BTEMP_THERMAL_MED_LIMIT         0
#define BTEMP_THERMAL_HIGH_LIMIT_52     52
#define BTEMP_THERMAL_HIGH_LIMIT_57     57
#define BTEMP_THERMAL_HIGH_LIMIT_62     62

#define BTEMP_BATCTRL_CURR_SRC_7UA      7
#define BTEMP_BATCTRL_CURR_SRC_20UA     20

#define BTEMP_BATCTRL_CURR_SRC_16UA     16
#define BTEMP_BATCTRL_CURR_SRC_18UA     18

#define BTEMP_BATCTRL_CURR_SRC_60UA     60
#define BTEMP_BATCTRL_CURR_SRC_120UA    120

/**
 * struct ab8500_btemp_interrupts - ab8500 interrupts
 * @name:       name of the interrupt
 * @isr         function pointer to the isr
 */
struct ab8500_btemp_interrupts {
        char *name;
        irqreturn_t (*isr)(int irq, void *data);
};

struct ab8500_btemp_events {
        bool batt_rem;
        bool btemp_high;
        bool btemp_medhigh;
        bool btemp_lowmed;
        bool btemp_low;
        bool ac_conn;
        bool usb_conn;
};

struct ab8500_btemp_ranges {
        int btemp_high_limit;
        int btemp_med_limit;
        int btemp_low_limit;
};

/**
 * struct ab8500_btemp - ab8500 BTEMP device information
 * @dev:                Pointer to the structure device
 * @node:               List of AB8500 BTEMPs, hence prepared for reentrance
 * @curr_source:        What current source we use, in uA
 * @bat_temp:           Dispatched battery temperature in degree Celsius
 * @prev_bat_temp       Last measured battery temperature in degree Celsius
 * @parent:             Pointer to the struct ab8500
 * @adc_btemp_ball:     ADC channel for the battery ball temperature
 * @adc_bat_ctrl:       ADC channel for the battery control
 * @fg:                 Pointer to the struct fg
 * @bm:                 Platform specific battery management information
 * @btemp_psy:          Structure for BTEMP specific battery properties
 * @events:             Structure for information about events triggered
 * @btemp_ranges:       Battery temperature range structure
 * @btemp_wq:           Work queue for measuring the temperature periodically
 * @btemp_periodic_work:        Work for measuring the temperature periodically
 * @initialized:        True if battery id read.
 */
struct ab8500_btemp {
        struct device *dev;
        struct list_head node;
        int curr_source;
        int bat_temp;
        int prev_bat_temp;
        struct ab8500 *parent;
        struct iio_channel *btemp_ball;
        struct iio_channel *bat_ctrl;
        struct ab8500_fg *fg;
        struct abx500_bm_data *bm;
        struct power_supply *btemp_psy;
        struct ab8500_btemp_events events;
        struct ab8500_btemp_ranges btemp_ranges;
        struct workqueue_struct *btemp_wq;
        struct delayed_work btemp_periodic_work;
        bool initialized;
};

/* BTEMP power supply properties */
static enum power_supply_property ab8500_btemp_props[] = {
        POWER_SUPPLY_PROP_PRESENT,
        POWER_SUPPLY_PROP_ONLINE,
        POWER_SUPPLY_PROP_TECHNOLOGY,
        POWER_SUPPLY_PROP_TEMP,
};

static LIST_HEAD(ab8500_btemp_list);

/**
 * ab8500_btemp_get() - returns a reference to the primary AB8500 BTEMP
 * (i.e. the first BTEMP in the instance list)
 */
struct ab8500_btemp *ab8500_btemp_get(void)
{
        return list_first_entry(&ab8500_btemp_list, struct ab8500_btemp, node);
}
EXPORT_SYMBOL(ab8500_btemp_get);

/**
 * ab8500_btemp_batctrl_volt_to_res() - convert batctrl voltage to resistance
 * @di:         pointer to the ab8500_btemp structure
 * @v_batctrl:  measured batctrl voltage
 * @inst_curr:  measured instant current
 *
 * This function returns the battery resistance that is
 * derived from the BATCTRL voltage.
 * Returns value in Ohms.
 */
static int ab8500_btemp_batctrl_volt_to_res(struct ab8500_btemp *di,
        int v_batctrl, int inst_curr)
{
        int rbs;

        if (is_ab8500_1p1_or_earlier(di->parent)) {
                /*
                 * For ABB cut1.0 and 1.1 BAT_CTRL is internally
                 * connected to 1.8V through a 450k resistor
                 */
                return (450000 * (v_batctrl)) / (1800 - v_batctrl);
        }

        if (di->bm->adc_therm == ABx500_ADC_THERM_BATCTRL) {
                /*
                 * If the battery has internal NTC, we use the current
                 * source to calculate the resistance.
                 */
                rbs = (v_batctrl * 1000
                       - di->bm->gnd_lift_resistance * inst_curr)
                      / di->curr_source;
        } else {
                /*
                 * BAT_CTRL is internally
                 * connected to 1.8V through a 80k resistor
                 */
                rbs = (80000 * (v_batctrl)) / (1800 - v_batctrl);
        }

        return rbs;
}

/**
 * ab8500_btemp_read_batctrl_voltage() - measure batctrl voltage
 * @di:         pointer to the ab8500_btemp structure
 *
 * This function returns the voltage on BATCTRL. Returns value in mV.
 */
static int ab8500_btemp_read_batctrl_voltage(struct ab8500_btemp *di)
{
        int vbtemp, ret;
        static int prev;

        ret = iio_read_channel_processed(di->bat_ctrl, &vbtemp);
        if (ret < 0) {
                dev_err(di->dev,
                        "%s ADC conversion failed, using previous value",
                        __func__);
                return prev;
        }
        prev = vbtemp;
        return vbtemp;
}

/**
 * ab8500_btemp_curr_source_enable() - enable/disable batctrl current source
 * @di:         pointer to the ab8500_btemp structure
 * @enable:     enable or disable the current source
 *
 * Enable or disable the current sources for the BatCtrl AD channel
 */
static int ab8500_btemp_curr_source_enable(struct ab8500_btemp *di,
        bool enable)
{
        int curr;
        int ret = 0;

        /*
         * BATCTRL current sources are included on AB8500 cut2.0
         * and future versions
         */
        if (is_ab8500_1p1_or_earlier(di->parent))
                return 0;

        /* Only do this for batteries with internal NTC */
        if (di->bm->adc_therm == ABx500_ADC_THERM_BATCTRL && enable) {

                if (di->curr_source == BTEMP_BATCTRL_CURR_SRC_7UA)
                        curr = BAT_CTRL_7U_ENA;
                else
                        curr = BAT_CTRL_20U_ENA;

                dev_dbg(di->dev, "Set BATCTRL %duA\n", di->curr_source);

                ret = abx500_mask_and_set_register_interruptible(di->dev,
                        AB8500_CHARGER, AB8500_BAT_CTRL_CURRENT_SOURCE,
                        FORCE_BAT_CTRL_CMP_HIGH, FORCE_BAT_CTRL_CMP_HIGH);
                if (ret) {
                        dev_err(di->dev, "%s failed setting cmp_force\n",
                                __func__);
                        return ret;
                }

                /*
                 * We have to wait one 32kHz cycle before enabling
                 * the current source, since ForceBatCtrlCmpHigh needs
                 * to be written in a separate cycle
                 */
                udelay(32);

                ret = abx500_set_register_interruptible(di->dev,
                        AB8500_CHARGER, AB8500_BAT_CTRL_CURRENT_SOURCE,
                        FORCE_BAT_CTRL_CMP_HIGH | curr);
                if (ret) {
                        dev_err(di->dev, "%s failed enabling current source\n",
                                __func__);
                        goto disable_curr_source;
                }
        } else if (di->bm->adc_therm == ABx500_ADC_THERM_BATCTRL && !enable) {
                dev_dbg(di->dev, "Disable BATCTRL curr source\n");

                /* Write 0 to the curr bits */
                ret = abx500_mask_and_set_register_interruptible(
                        di->dev,
                        AB8500_CHARGER, AB8500_BAT_CTRL_CURRENT_SOURCE,
                        BAT_CTRL_7U_ENA | BAT_CTRL_20U_ENA,
                        ~(BAT_CTRL_7U_ENA | BAT_CTRL_20U_ENA));

                if (ret) {
                        dev_err(di->dev, "%s failed disabling current source\n",
                                __func__);
                        goto disable_curr_source;
                }

                /* Enable Pull-Up and comparator */
                ret = abx500_mask_and_set_register_interruptible(di->dev,
                        AB8500_CHARGER, AB8500_BAT_CTRL_CURRENT_SOURCE,
                        BAT_CTRL_PULL_UP_ENA | BAT_CTRL_CMP_ENA,
                        BAT_CTRL_PULL_UP_ENA | BAT_CTRL_CMP_ENA);
                if (ret) {
                        dev_err(di->dev, "%s failed enabling PU and comp\n",
                                __func__);
                        goto enable_pu_comp;
                }

                /*
                 * We have to wait one 32kHz cycle before disabling
                 * ForceBatCtrlCmpHigh since this needs to be written
                 * in a separate cycle
                 */
                udelay(32);

                /* Disable 'force comparator' */
                ret = abx500_mask_and_set_register_interruptible(di->dev,
                        AB8500_CHARGER, AB8500_BAT_CTRL_CURRENT_SOURCE,
                        FORCE_BAT_CTRL_CMP_HIGH, ~FORCE_BAT_CTRL_CMP_HIGH);
                if (ret) {
                        dev_err(di->dev, "%s failed disabling force comp\n",
                                __func__);
                        goto disable_force_comp;
                }
        }
        return ret;

        /*
         * We have to try unsetting FORCE_BAT_CTRL_CMP_HIGH one more time
         * if we got an error above
         */
disable_curr_source:
        /* Write 0 to the curr bits */
        ret = abx500_mask_and_set_register_interruptible(di->dev,
                AB8500_CHARGER, AB8500_BAT_CTRL_CURRENT_SOURCE,
                BAT_CTRL_7U_ENA | BAT_CTRL_20U_ENA,
                ~(BAT_CTRL_7U_ENA | BAT_CTRL_20U_ENA));

        if (ret) {
                dev_err(di->dev, "%s failed disabling current source\n",
                        __func__);
                return ret;
        }
enable_pu_comp:
        /* Enable Pull-Up and comparator */
        ret = abx500_mask_and_set_register_interruptible(di->dev,
                AB8500_CHARGER, AB8500_BAT_CTRL_CURRENT_SOURCE,
                BAT_CTRL_PULL_UP_ENA | BAT_CTRL_CMP_ENA,
                BAT_CTRL_PULL_UP_ENA | BAT_CTRL_CMP_ENA);
        if (ret) {
                dev_err(di->dev, "%s failed enabling PU and comp\n",
                        __func__);
                return ret;
        }

disable_force_comp:
        /*
         * We have to wait one 32kHz cycle before disabling
         * ForceBatCtrlCmpHigh since this needs to be written
         * in a separate cycle
         */
        udelay(32);

        /* Disable 'force comparator' */
        ret = abx500_mask_and_set_register_interruptible(di->dev,
                AB8500_CHARGER, AB8500_BAT_CTRL_CURRENT_SOURCE,
                FORCE_BAT_CTRL_CMP_HIGH, ~FORCE_BAT_CTRL_CMP_HIGH);
        if (ret) {
                dev_err(di->dev, "%s failed disabling force comp\n",
                        __func__);
                return ret;
        }

        return ret;
}

/**
 * ab8500_btemp_get_batctrl_res() - get battery resistance
 * @di:         pointer to the ab8500_btemp structure
 *
 * This function returns the battery pack identification resistance.
 * Returns value in Ohms.
 */
static int ab8500_btemp_get_batctrl_res(struct ab8500_btemp *di)
{
        int ret;
        int batctrl = 0;
        int res;
        int inst_curr;
        int i;

        /*
         * BATCTRL current sources are included on AB8500 cut2.0
         * and future versions
         */
        ret = ab8500_btemp_curr_source_enable(di, true);
        if (ret) {
                dev_err(di->dev, "%s curr source enabled failed\n", __func__);
                return ret;
        }

        if (!di->fg)
                di->fg = ab8500_fg_get();
        if (!di->fg) {
                dev_err(di->dev, "No fg found\n");
                return -EINVAL;
        }

        ret = ab8500_fg_inst_curr_start(di->fg);

        if (ret) {
                dev_err(di->dev, "Failed to start current measurement\n");
                return ret;
        }

        do {
                msleep(20);
        } while (!ab8500_fg_inst_curr_started(di->fg));

        i = 0;

        do {
                batctrl += ab8500_btemp_read_batctrl_voltage(di);
                i++;
                msleep(20);
        } while (!ab8500_fg_inst_curr_done(di->fg));
        batctrl /= i;

        ret = ab8500_fg_inst_curr_finalize(di->fg, &inst_curr);
        if (ret) {
                dev_err(di->dev, "Failed to finalize current measurement\n");
                return ret;
        }

        res = ab8500_btemp_batctrl_volt_to_res(di, batctrl, inst_curr);

        ret = ab8500_btemp_curr_source_enable(di, false);
        if (ret) {
                dev_err(di->dev, "%s curr source disable failed\n", __func__);
                return ret;
        }

        dev_dbg(di->dev, "%s batctrl: %d res: %d inst_curr: %d samples: %d\n",
                __func__, batctrl, res, inst_curr, i);

        return res;
}

/**
 * ab8500_btemp_res_to_temp() - resistance to temperature
 * @di:         pointer to the ab8500_btemp structure
 * @tbl:        pointer to the resiatance to temperature table
 * @tbl_size:   size of the resistance to temperature table
 * @res:        resistance to calculate the temperature from
 *
 * This function returns the battery temperature in degrees Celsius
 * based on the NTC resistance.
 */
static int ab8500_btemp_res_to_temp(struct ab8500_btemp *di,
        const struct abx500_res_to_temp *tbl, int tbl_size, int res)
{
        int i;
        /*
         * Calculate the formula for the straight line
         * Simple interpolation if we are within
         * the resistance table limits, extrapolate
         * if resistance is outside the limits.
         */
        if (res > tbl[0].resist)
                i = 0;
        else if (res <= tbl[tbl_size - 1].resist)
                i = tbl_size - 2;
        else {
                i = 0;
                while (!(res <= tbl[i].resist &&
                        res > tbl[i + 1].resist))
                        i++;
        }

        return tbl[i].temp + ((tbl[i + 1].temp - tbl[i].temp) *
                (res - tbl[i].resist)) / (tbl[i + 1].resist - tbl[i].resist);
}

/**
 * ab8500_btemp_measure_temp() - measure battery temperature
 * @di:         pointer to the ab8500_btemp structure
 *
 * Returns battery temperature (on success) else the previous temperature
 */
static int ab8500_btemp_measure_temp(struct ab8500_btemp *di)
{
        int temp, ret;
        static int prev;
        int rbat, rntc, vntc;
        u8 id;

        id = di->bm->batt_id;

        if (di->bm->adc_therm == ABx500_ADC_THERM_BATCTRL &&
                        id != BATTERY_UNKNOWN) {

                rbat = ab8500_btemp_get_batctrl_res(di);
                if (rbat < 0) {
                        dev_err(di->dev, "%s get batctrl res failed\n",
                                __func__);
                        /*
                         * Return out-of-range temperature so that
                         * charging is stopped
                         */
                        return BTEMP_THERMAL_LOW_LIMIT;
                }

                temp = ab8500_btemp_res_to_temp(di,
                        di->bm->bat_type[id].r_to_t_tbl,
                        di->bm->bat_type[id].n_temp_tbl_elements, rbat);
        } else {
                ret = iio_read_channel_processed(di->btemp_ball, &vntc);
                if (ret < 0) {
                        dev_err(di->dev,
                                "%s ADC conversion failed,"
                                " using previous value\n", __func__);
                        return prev;
                }
                /*
                 * The PCB NTC is sourced from VTVOUT via a 230kOhm
                 * resistor.
                 */
                rntc = 230000 * vntc / (VTVOUT_V - vntc);

                temp = ab8500_btemp_res_to_temp(di,
                        di->bm->bat_type[id].r_to_t_tbl,
                        di->bm->bat_type[id].n_temp_tbl_elements, rntc);
                prev = temp;
        }
        dev_dbg(di->dev, "Battery temperature is %d\n", temp);
        return temp;
}

/**
 * ab8500_btemp_id() - Identify the connected battery
 * @di:         pointer to the ab8500_btemp structure
 *
 * This function will try to identify the battery by reading the ID
 * resistor. Some brands use a combined ID resistor with a NTC resistor to
 * both be able to identify and to read the temperature of it.
 */
static int ab8500_btemp_id(struct ab8500_btemp *di)
{
        int res;
        u8 i;

        di->curr_source = BTEMP_BATCTRL_CURR_SRC_7UA;
        di->bm->batt_id = BATTERY_UNKNOWN;

        res =  ab8500_btemp_get_batctrl_res(di);
        if (res < 0) {
                dev_err(di->dev, "%s get batctrl res failed\n", __func__);
                return -ENXIO;
        }

        /* BATTERY_UNKNOWN is defined on position 0, skip it! */
        for (i = BATTERY_UNKNOWN + 1; i < di->bm->n_btypes; i++) {
                if ((res <= di->bm->bat_type[i].resis_high) &&
                        (res >= di->bm->bat_type[i].resis_low)) {
                        dev_dbg(di->dev, "Battery detected on %s"
                                " low %d < res %d < high: %d"
                                " index: %d\n",
                                di->bm->adc_therm == ABx500_ADC_THERM_BATCTRL ?
                                "BATCTRL" : "BATTEMP",
                                di->bm->bat_type[i].resis_low, res,
                                di->bm->bat_type[i].resis_high, i);

                        di->bm->batt_id = i;
                        break;
                }
        }

        if (di->bm->batt_id == BATTERY_UNKNOWN) {
                dev_warn(di->dev, "Battery identified as unknown"
                        ", resistance %d Ohm\n", res);
                return -ENXIO;
        }

        /*
         * We only have to change current source if the
         * detected type is Type 1.
         */
        if (di->bm->adc_therm == ABx500_ADC_THERM_BATCTRL &&
            di->bm->batt_id == 1) {
                dev_dbg(di->dev, "Set BATCTRL current source to 20uA\n");
                di->curr_source = BTEMP_BATCTRL_CURR_SRC_20UA;
        }

        return di->bm->batt_id;
}

/**
 * ab8500_btemp_periodic_work() - Measuring the temperature periodically
 * @work:       pointer to the work_struct structure
 *
 * Work function for measuring the temperature periodically
 */
static void ab8500_btemp_periodic_work(struct work_struct *work)
{
        int interval;
        int bat_temp;
        struct ab8500_btemp *di = container_of(work,
                struct ab8500_btemp, btemp_periodic_work.work);

        if (!di->initialized) {
                /* Identify the battery */
                if (ab8500_btemp_id(di) < 0)
                        dev_warn(di->dev, "failed to identify the battery\n");
        }

        bat_temp = ab8500_btemp_measure_temp(di);
        /*
         * Filter battery temperature.
         * Allow direct updates on temperature only if two samples result in
         * same temperature. Else only allow 1 degree change from previous
         * reported value in the direction of the new measurement.
         */
        if ((bat_temp == di->prev_bat_temp) || !di->initialized) {
                if ((di->bat_temp != di->prev_bat_temp) || !di->initialized) {
                        di->initialized = true;
                        di->bat_temp = bat_temp;
                        power_supply_changed(di->btemp_psy);
                }
        } else if (bat_temp < di->prev_bat_temp) {
                di->bat_temp--;
                power_supply_changed(di->btemp_psy);
        } else if (bat_temp > di->prev_bat_temp) {
                di->bat_temp++;
                power_supply_changed(di->btemp_psy);
        }
        di->prev_bat_temp = bat_temp;

        if (di->events.ac_conn || di->events.usb_conn)
                interval = di->bm->temp_interval_chg;
        else
                interval = di->bm->temp_interval_nochg;

        /* Schedule a new measurement */
        queue_delayed_work(di->btemp_wq,
                &di->btemp_periodic_work,
                round_jiffies(interval * HZ));
}

/**
 * ab8500_btemp_batctrlindb_handler() - battery removal detected
 * @irq:       interrupt number
 * @_di:       void pointer that has to address of ab8500_btemp
 *
 * Returns IRQ status(IRQ_HANDLED)
 */
static irqreturn_t ab8500_btemp_batctrlindb_handler(int irq, void *_di)
{
        struct ab8500_btemp *di = _di;
        dev_err(di->dev, "Battery removal detected!\n");

        di->events.batt_rem = true;
        power_supply_changed(di->btemp_psy);

        return IRQ_HANDLED;
}

/**
 * ab8500_btemp_templow_handler() - battery temp lower than 10 degrees
 * @irq:       interrupt number
 * @_di:       void pointer that has to address of ab8500_btemp
 *
 * Returns IRQ status(IRQ_HANDLED)
 */
static irqreturn_t ab8500_btemp_templow_handler(int irq, void *_di)
{
        struct ab8500_btemp *di = _di;

        if (is_ab8500_3p3_or_earlier(di->parent)) {
                dev_dbg(di->dev, "Ignore false btemp low irq"
                        " for ABB cut 1.0, 1.1, 2.0 and 3.3\n");
        } else {
                dev_crit(di->dev, "Battery temperature lower than -10deg c\n");

                di->events.btemp_low = true;
                di->events.btemp_high = false;
                di->events.btemp_medhigh = false;
                di->events.btemp_lowmed = false;
                power_supply_changed(di->btemp_psy);
        }

        return IRQ_HANDLED;
}

/**
 * ab8500_btemp_temphigh_handler() - battery temp higher than max temp
 * @irq:       interrupt number
 * @_di:       void pointer that has to address of ab8500_btemp
 *
 * Returns IRQ status(IRQ_HANDLED)
 */
static irqreturn_t ab8500_btemp_temphigh_handler(int irq, void *_di)
{
        struct ab8500_btemp *di = _di;

        dev_crit(di->dev, "Battery temperature is higher than MAX temp\n");

        di->events.btemp_high = true;
        di->events.btemp_medhigh = false;
        di->events.btemp_lowmed = false;
        di->events.btemp_low = false;
        power_supply_changed(di->btemp_psy);

        return IRQ_HANDLED;
}

/**
 * ab8500_btemp_lowmed_handler() - battery temp between low and medium
 * @irq:       interrupt number
 * @_di:       void pointer that has to address of ab8500_btemp
 *
 * Returns IRQ status(IRQ_HANDLED)
 */
static irqreturn_t ab8500_btemp_lowmed_handler(int irq, void *_di)
{
        struct ab8500_btemp *di = _di;

        dev_dbg(di->dev, "Battery temperature is between low and medium\n");

        di->events.btemp_lowmed = true;
        di->events.btemp_medhigh = false;
        di->events.btemp_high = false;
        di->events.btemp_low = false;
        power_supply_changed(di->btemp_psy);

        return IRQ_HANDLED;
}

/**
 * ab8500_btemp_medhigh_handler() - battery temp between medium and high
 * @irq:       interrupt number
 * @_di:       void pointer that has to address of ab8500_btemp
 *
 * Returns IRQ status(IRQ_HANDLED)
 */
static irqreturn_t ab8500_btemp_medhigh_handler(int irq, void *_di)
{
        struct ab8500_btemp *di = _di;

        dev_dbg(di->dev, "Battery temperature is between medium and high\n");

        di->events.btemp_medhigh = true;
        di->events.btemp_lowmed = false;
        di->events.btemp_high = false;
        di->events.btemp_low = false;
        power_supply_changed(di->btemp_psy);

        return IRQ_HANDLED;
}

/**
 * ab8500_btemp_periodic() - Periodic temperature measurements
 * @di:         pointer to the ab8500_btemp structure
 * @enable:     enable or disable periodic temperature measurements
 *
 * Starts of stops periodic temperature measurements. Periodic measurements
 * should only be done when a charger is connected.
 */
static void ab8500_btemp_periodic(struct ab8500_btemp *di,
        bool enable)
{
        dev_dbg(di->dev, "Enable periodic temperature measurements: %d\n",
                enable);
        /*
         * Make sure a new measurement is done directly by cancelling
         * any pending work
         */
        cancel_delayed_work_sync(&di->btemp_periodic_work);

        if (enable)
                queue_delayed_work(di->btemp_wq, &di->btemp_periodic_work, 0);
}

/**
 * ab8500_btemp_get_temp() - get battery temperature
 * @di:         pointer to the ab8500_btemp structure
 *
 * Returns battery temperature
 */
int ab8500_btemp_get_temp(struct ab8500_btemp *di)
{
        int temp = 0;

        /*
         * The BTEMP events are not reliabe on AB8500 cut3.3
         * and prior versions
         */
        if (is_ab8500_3p3_or_earlier(di->parent)) {
                temp = di->bat_temp * 10;
        } else {
                if (di->events.btemp_low) {
                        if (temp > di->btemp_ranges.btemp_low_limit)
                                temp = di->btemp_ranges.btemp_low_limit * 10;
                        else
                                temp = di->bat_temp * 10;
                } else if (di->events.btemp_high) {
                        if (temp < di->btemp_ranges.btemp_high_limit)
                                temp = di->btemp_ranges.btemp_high_limit * 10;
                        else
                                temp = di->bat_temp * 10;
                } else if (di->events.btemp_lowmed) {
                        if (temp > di->btemp_ranges.btemp_med_limit)
                                temp = di->btemp_ranges.btemp_med_limit * 10;
                        else
                                temp = di->bat_temp * 10;
                } else if (di->events.btemp_medhigh) {
                        if (temp < di->btemp_ranges.btemp_med_limit)
                                temp = di->btemp_ranges.btemp_med_limit * 10;
                        else
                                temp = di->bat_temp * 10;
                } else
                        temp = di->bat_temp * 10;
        }
        return temp;
}
EXPORT_SYMBOL(ab8500_btemp_get_temp);

/**
 * ab8500_btemp_get_batctrl_temp() - get the temperature
 * @btemp:      pointer to the btemp structure
 *
 * Returns the batctrl temperature in millidegrees
 */
int ab8500_btemp_get_batctrl_temp(struct ab8500_btemp *btemp)
{
        return btemp->bat_temp * 1000;
}
EXPORT_SYMBOL(ab8500_btemp_get_batctrl_temp);

/**
 * ab8500_btemp_get_property() - get the btemp properties
 * @psy:        pointer to the power_supply structure
 * @psp:        pointer to the power_supply_property structure
 * @val:        pointer to the power_supply_propval union
 *
 * This function gets called when an application tries to get the btemp
 * properties by reading the sysfs files.
 * online:      presence of the battery
 * present:     presence of the battery
 * technology:  battery technology
 * temp:        battery temperature
 * Returns error code in case of failure else 0(on success)
 */
static int ab8500_btemp_get_property(struct power_supply *psy,
        enum power_supply_property psp,
        union power_supply_propval *val)
{
        struct ab8500_btemp *di = power_supply_get_drvdata(psy);

        switch (psp) {
        case POWER_SUPPLY_PROP_PRESENT:
        case POWER_SUPPLY_PROP_ONLINE:
                if (di->events.batt_rem)
                        val->intval = 0;
                else
                        val->intval = 1;
                break;
        case POWER_SUPPLY_PROP_TECHNOLOGY:
                val->intval = di->bm->bat_type[di->bm->batt_id].name;
                break;
        case POWER_SUPPLY_PROP_TEMP:
                val->intval = ab8500_btemp_get_temp(di);
                break;
        default:
                return -EINVAL;
        }
        return 0;
}

static int ab8500_btemp_get_ext_psy_data(struct device *dev, void *data)
{
        struct power_supply *psy;
        struct power_supply *ext = dev_get_drvdata(dev);
        const char **supplicants = (const char **)ext->supplied_to;
        struct ab8500_btemp *di;
        union power_supply_propval ret;
        int j;

        psy = (struct power_supply *)data;
        di = power_supply_get_drvdata(psy);

        /*
         * For all psy where the name of your driver
         * appears in any supplied_to
         */
        j = match_string(supplicants, ext->num_supplicants, psy->desc->name);
        if (j < 0)
                return 0;

        /* Go through all properties for the psy */
        for (j = 0; j < ext->desc->num_properties; j++) {
                enum power_supply_property prop;
                prop = ext->desc->properties[j];

                if (power_supply_get_property(ext, prop, &ret))
                        continue;

                switch (prop) {
                case POWER_SUPPLY_PROP_PRESENT:
                        switch (ext->desc->type) {
                        case POWER_SUPPLY_TYPE_MAINS:
                                /* AC disconnected */
                                if (!ret.intval && di->events.ac_conn) {
                                        di->events.ac_conn = false;
                                }
                                /* AC connected */
                                else if (ret.intval && !di->events.ac_conn) {
                                        di->events.ac_conn = true;
                                        if (!di->events.usb_conn)
                                                ab8500_btemp_periodic(di, true);
                                }
                                break;
                        case POWER_SUPPLY_TYPE_USB:
                                /* USB disconnected */
                                if (!ret.intval && di->events.usb_conn) {
                                        di->events.usb_conn = false;
                                }
                                /* USB connected */
                                else if (ret.intval && !di->events.usb_conn) {
                                        di->events.usb_conn = true;
                                        if (!di->events.ac_conn)
                                                ab8500_btemp_periodic(di, true);
                                }
                                break;
                        default:
                                break;
                        }
                        break;
                default:
                        break;
                }
        }
        return 0;
}

/**
 * ab8500_btemp_external_power_changed() - callback for power supply changes
 * @psy:       pointer to the structure power_supply
 *
 * This function is pointing to the function pointer external_power_changed
 * of the structure power_supply.
 * This function gets executed when there is a change in the external power
 * supply to the btemp.
 */
static void ab8500_btemp_external_power_changed(struct power_supply *psy)
{
        struct ab8500_btemp *di = power_supply_get_drvdata(psy);

        class_for_each_device(power_supply_class, NULL,
                di->btemp_psy, ab8500_btemp_get_ext_psy_data);
}

/* ab8500 btemp driver interrupts and their respective isr */
static struct ab8500_btemp_interrupts ab8500_btemp_irq[] = {
        {"BAT_CTRL_INDB", ab8500_btemp_batctrlindb_handler},
        {"BTEMP_LOW", ab8500_btemp_templow_handler},
        {"BTEMP_HIGH", ab8500_btemp_temphigh_handler},
        {"BTEMP_LOW_MEDIUM", ab8500_btemp_lowmed_handler},
        {"BTEMP_MEDIUM_HIGH", ab8500_btemp_medhigh_handler},
};

#if defined(CONFIG_PM)
static int ab8500_btemp_resume(struct platform_device *pdev)
{
        struct ab8500_btemp *di = platform_get_drvdata(pdev);

        ab8500_btemp_periodic(di, true);

        return 0;
}

static int ab8500_btemp_suspend(struct platform_device *pdev,
        pm_message_t state)
{
        struct ab8500_btemp *di = platform_get_drvdata(pdev);

        ab8500_btemp_periodic(di, false);

        return 0;
}
#else
#define ab8500_btemp_suspend      NULL
#define ab8500_btemp_resume       NULL
#endif

static int ab8500_btemp_remove(struct platform_device *pdev)
{
        struct ab8500_btemp *di = platform_get_drvdata(pdev);
        int i, irq;

        /* Disable interrupts */
        for (i = 0; i < ARRAY_SIZE(ab8500_btemp_irq); i++) {
                irq = platform_get_irq_byname(pdev, ab8500_btemp_irq[i].name);
                free_irq(irq, di);
        }

        /* Delete the work queue */
        destroy_workqueue(di->btemp_wq);

        flush_scheduled_work();
        power_supply_unregister(di->btemp_psy);

        return 0;
}

static char *supply_interface[] = {
        "ab8500_chargalg",
        "ab8500_fg",
};

static const struct power_supply_desc ab8500_btemp_desc = {
        .name                   = "ab8500_btemp",
        .type                   = POWER_SUPPLY_TYPE_BATTERY,
        .properties             = ab8500_btemp_props,
        .num_properties         = ARRAY_SIZE(ab8500_btemp_props),
        .get_property           = ab8500_btemp_get_property,
        .external_power_changed = ab8500_btemp_external_power_changed,
};

static int ab8500_btemp_probe(struct platform_device *pdev)
{
        struct device_node *np = pdev->dev.of_node;
        struct abx500_bm_data *plat = pdev->dev.platform_data;

        struct power_supply_config psy_cfg = {};
        struct ab8500_btemp *di;
        int irq, i, ret = 0;
        u8 val;

        di = devm_kzalloc(&pdev->dev, sizeof(*di), GFP_KERNEL);
        if (!di) {
                dev_err(&pdev->dev, "%s no mem for ab8500_btemp\n", __func__);
                return -ENOMEM;
        }

        if (!plat) {
                dev_err(&pdev->dev, "no battery management data supplied\n");
                return -EINVAL;
        }
        di->bm = plat;

        if (np) {
                ret = ab8500_bm_of_probe(&pdev->dev, np, di->bm);
                if (ret) {
                        dev_err(&pdev->dev, "failed to get battery information\n");
                        return ret;
                }
        }

        /* get parent data */
        di->dev = &pdev->dev;
        di->parent = dev_get_drvdata(pdev->dev.parent);

        /* Get ADC channels */
        di->btemp_ball = devm_iio_channel_get(&pdev->dev, "btemp_ball");
        if (IS_ERR(di->btemp_ball)) {
                if (PTR_ERR(di->btemp_ball) == -ENODEV)
                        return -EPROBE_DEFER;
                dev_err(&pdev->dev, "failed to get BTEMP BALL ADC channel\n");
                return PTR_ERR(di->btemp_ball);
        }
        di->bat_ctrl = devm_iio_channel_get(&pdev->dev, "bat_ctrl");
        if (IS_ERR(di->bat_ctrl)) {
                if (PTR_ERR(di->bat_ctrl) == -ENODEV)
                        return -EPROBE_DEFER;
                dev_err(&pdev->dev, "failed to get BAT CTRL ADC channel\n");
                return PTR_ERR(di->bat_ctrl);
        }

        di->initialized = false;

        psy_cfg.supplied_to = supply_interface;
        psy_cfg.num_supplicants = ARRAY_SIZE(supply_interface);
        psy_cfg.drv_data = di;

        /* Create a work queue for the btemp */
        di->btemp_wq =
                alloc_workqueue("ab8500_btemp_wq", WQ_MEM_RECLAIM, 0);
        if (di->btemp_wq == NULL) {
                dev_err(di->dev, "failed to create work queue\n");
                return -ENOMEM;
        }

        /* Init work for measuring temperature periodically */
        INIT_DEFERRABLE_WORK(&di->btemp_periodic_work,
                ab8500_btemp_periodic_work);

        /* Set BTEMP thermal limits. Low and Med are fixed */
        di->btemp_ranges.btemp_low_limit = BTEMP_THERMAL_LOW_LIMIT;
        di->btemp_ranges.btemp_med_limit = BTEMP_THERMAL_MED_LIMIT;

        ret = abx500_get_register_interruptible(di->dev, AB8500_CHARGER,
                AB8500_BTEMP_HIGH_TH, &val);
        if (ret < 0) {
                dev_err(di->dev, "%s ab8500 read failed\n", __func__);
                goto free_btemp_wq;
        }
        switch (val) {
        case BTEMP_HIGH_TH_57_0:
        case BTEMP_HIGH_TH_57_1:
                di->btemp_ranges.btemp_high_limit =
                        BTEMP_THERMAL_HIGH_LIMIT_57;
                break;
        case BTEMP_HIGH_TH_52:
                di->btemp_ranges.btemp_high_limit =
                        BTEMP_THERMAL_HIGH_LIMIT_52;
                break;
        case BTEMP_HIGH_TH_62:
                di->btemp_ranges.btemp_high_limit =
                        BTEMP_THERMAL_HIGH_LIMIT_62;
                break;
        }

        /* Register BTEMP power supply class */
        di->btemp_psy = power_supply_register(di->dev, &ab8500_btemp_desc,
                                              &psy_cfg);
        if (IS_ERR(di->btemp_psy)) {
                dev_err(di->dev, "failed to register BTEMP psy\n");
                ret = PTR_ERR(di->btemp_psy);
                goto free_btemp_wq;
        }

        /* Register interrupts */
        for (i = 0; i < ARRAY_SIZE(ab8500_btemp_irq); i++) {
                irq = platform_get_irq_byname(pdev, ab8500_btemp_irq[i].name);
                if (irq < 0) {
                        ret = irq;
                        goto free_irq;
                }

                ret = request_threaded_irq(irq, NULL, ab8500_btemp_irq[i].isr,
                        IRQF_SHARED | IRQF_NO_SUSPEND,
                        ab8500_btemp_irq[i].name, di);

                if (ret) {
                        dev_err(di->dev, "failed to request %s IRQ %d: %d\n"
                                , ab8500_btemp_irq[i].name, irq, ret);
                        goto free_irq;
                }
                dev_dbg(di->dev, "Requested %s IRQ %d: %d\n",
                        ab8500_btemp_irq[i].name, irq, ret);
        }

        platform_set_drvdata(pdev, di);

        /* Kick off periodic temperature measurements */
        ab8500_btemp_periodic(di, true);
        list_add_tail(&di->node, &ab8500_btemp_list);

        return ret;

free_irq:
        /* We also have to free all successfully registered irqs */
        for (i = i - 1; i >= 0; i--) {
                irq = platform_get_irq_byname(pdev, ab8500_btemp_irq[i].name);
                free_irq(irq, di);
        }

        power_supply_unregister(di->btemp_psy);
free_btemp_wq:
        destroy_workqueue(di->btemp_wq);
        return ret;
}

static const struct of_device_id ab8500_btemp_match[] = {
        { .compatible = "stericsson,ab8500-btemp", },
        { },
};

static struct platform_driver ab8500_btemp_driver = {
        .probe = ab8500_btemp_probe,
        .remove = ab8500_btemp_remove,
        .suspend = ab8500_btemp_suspend,
        .resume = ab8500_btemp_resume,
        .driver = {
                .name = "ab8500-btemp",
                .of_match_table = ab8500_btemp_match,
        },
};

static int __init ab8500_btemp_init(void)
{
        return platform_driver_register(&ab8500_btemp_driver);
}

static void __exit ab8500_btemp_exit(void)
{
        platform_driver_unregister(&ab8500_btemp_driver);
}

device_initcall(ab8500_btemp_init);
module_exit(ab8500_btemp_exit);

MODULE_LICENSE("GPL v2");
MODULE_AUTHOR("Johan Palsson, Karl Komierowski, Arun R Murthy");
MODULE_ALIAS("platform:ab8500-btemp");
MODULE_DESCRIPTION("AB8500 battery temperature driver");